1. Technical Field
The present invention relates to a method of providing video-call service using a general voice-call terminal and a Private Branch Exchange (PBX) for performing the method.
2. Related Art
As more and more voice communication networks are employing a packet switching technique rather than a circuit switching technique, and Internet Protocol (IP)-based communication is becoming increasingly widespread, Session Initiation Protocol (SIP) is becoming a main standard of IP-based communication. In addition, due to efforts to provide a service differentiated from conventional voice communication service in an IP network, a variety of SIP-based video communication equipment and solutions are appearing. In order to use such SIP-based video communication service, all terminals not supporting SIP video must be replaced.
In a conventional Private Branch Exchange (PBX), a digital phone and an analog phone based on a circuit serving only voice, a packet-based IP voice communication terminal, a native-protocol video communication terminal not supporting SIP, an SIP-supported videophone terminal, etc. can interwork with each other. In this case, the PBX is connected to its own or an external media gateway, an SIP proxy server, etc., and can provide voice-call service between all terminals, and video-call service between videophones using the same protocol.
According to the conventional art, terminals need to be replaced to provide video-call service to a user of a telephone that does not have a video screen. In addition, a method of providing video-call service between an IP videophone terminal not supporting SIP and an SIP videophone terminal has not yet been provided.